Digital projectors, such as digital mirror devices (DMD) and liquid crystal display (LCD) projectors, project high-quality images onto a viewing surface. Both DMD and LCD projectors utilize high-intensity burners and reflectors to generate the light needed for projection. Light generated by the burner is concentrated as a “fireball” that is located at a focal point of a reflector. Light produced by the fireball is directed into a projection assembly that produces images and utilizes the generated light to form the image. The image is then projected onto a viewing surface.
Efforts have been directed at making projectors more compact while making the image of higher and better quality. As a result, the lamps utilized have become more compact and of higher intensity. An example of one type of such lamp is a xenon lamp. Xenon lamps provide a relatively constant spectral output with significantly more output than other types of lamps without using substantial amounts of environmentally harmful materials, such as mercury. In addition, xenon lamps have the ability to hot strike and subsequently turn on at near full power.
Xenon lamps include an anode and a cathode. The anode and cathode are precisely positioned relative to one another such that a gap is established between them. The application of a voltage to the cathode causes the voltage to arc to the anode in the presence of the pressurized xenon gas, thereby generating light. In addition to generating light, the xenon lamp also produces thermal energy. As per the ideal gas law, as this thermal energy raises the temperature of the xenon lamp, the pressure in the xenon lamp must also rise. In order for the lamp to remain operational, the xenon gas within the lamp assembly must be retained.